Once upon a time, Garfield Logan was bitten by the Green-Capped Mangabey, the green monkey. The bite gave him a disease called Sakutia and to save him, his parents used his DNA alongside their universal cure research to create a cure for his disease.
In the present, Beast Boy is sick for the first time since he was six years old. However, at the same time so are dozens of kids across the city. After visiting the doctor, the Titans wander back home.
Meanwhile in Gotham City, Superboy looks for Robin but only manages to find Stephanie, the new Robin. They get into a fight, which Batman breaks up. He denies Superboy's request to get Tim's address and tells him to figure it out for himself.
Back in San Francisco, green animals are rampaging through the city, but when Beast Boy attempts to change forms, his skin color fades back into a normal pink tone.

This storyline is in direct response to the "all new, for the first time" Doom Patrol, whose past was entirely retconned out of DC history. Because the Doom Patrol was so central to Beast Boy's past, his origin required rewriting.